1. Field of the Invention
This invention relates to chain saws, and particularly to a safety attachment for a chain saw that functions as a deflector of small diameter branches.
2. Description of the Prior Art
A preliminary patentability and novelty search in connection with this invention has revealed the existence of four United States patents that are directed to safety attachments for chain saws. These patents are as follows:
______________________________________ 3,380,493 3,384,136 4,060,894 4,335,513 ______________________________________
A review of these patents indicates that while the structures disclosed are attachments for chain saws, the purpose of the attachment is entirely different from the purpose of the present invention. It is very well known among chain saw operators with hands-on experience that chain saws tend to kick back toward the operator if the end of the chain saw remote from the operator strickes a log or branch. The patents listed above disclose safety devices that minimize or eliminate the tendency of kick-back of a chain saw, or minimize the danger therefrom.
Experienced chain saw operators are aware that both the top and bottom reaches of the chain of a chain saw may be used to cut branches. Usually, however, it is the bottom reach of the chain that is used most. It has been found that when the bottom reach of the chain engages a substantial branch having appreciable thickness, the pull of the chain teeth against the branch tends to pull the housing of the saw toward the branch. Many models of chain saws take advantage of this tendency and provide sharp projections on the front surface of the housing that function not unlike teeth to bite into the branch, facilitating a rocking motion of the chain saw as it penetrates the thickness of the branch. This tendency to pull the saw housing toward the substantial branch being cut is due to the fact that the branch itself is relatively inflexible, while the saw is particularly mobile and is dragged forward by the chain.
However, when brush and small flexible branches are attempted to be cut with a chain saw, particularly with the lower reach of the chain saw, there is a tendency for the chain saw teeth to bite into the thin flexible branch or brush and whip it at high velocity toward the operator of the saw before the chain cuts the flexible branch. The impact of such flexible branches can be painful to the operator, can cause injury to the operator in addition to pain, and can cause the operator to flinch in such a manner that may cause loss of balance, which can lead to much more serious injury from the rotating chain of the chain saw.
Accordingly, it is one of the important objects of the present invention to provide a safety attachment for the blade of a chain saw that deflects the rearward whip of small branches by the chain saw, and which will also function as an abutment to prevent the saw from being pulled forwardly by the chain when larger less flexible branches are cut with the chain saw.
It frequently happens that it is desirable to use the chain saw for larger branches without the impediment of a safety attachment. Accordingly, it is another object of the invention to provide a safety attachment for chain saws that may be easily applied for use when needed for cutting small diameter flexible branches, and may be just as easily removed for use of the chain saw without the safety attachment.
The popularity of the chain saw has skyrocketed in the recent past. The cost of very effective large and small chain saws has been reduced considerably since the chain saw was first introduced, and as a consequence, many people now own chain saws that use them only infrequently, and for short lengths of time, for cutting small shrubs and brush as distinguished from the larger type chain saws used to cut down full-grown trees in the forests, for example. Accordingly, it is another object of the invention to provide a chain saw safety attachment as an article of manufacture that may be applied to the blades or chain guides of chain saws that are already in existence.
When working with a chain saw, it is an advantage from the point of view of safety that the operator not carry metallic tools, or wear loose clothing, or carry pouches in which tools may be carried, that pose the possibility of becoming entangled with the chain of the chain saw. Accordingly, a still further object of the invention is the provision of a safety attachment for chain saws that may be applied and removed from the chain saw without the use of tools.
To apply the safety attachment of my invention to a chain saw that one already owns, it is necessary that two small apertures be bored in the chain saw blade or chain guide plate. Since most of these blades or guide plates are hardened to withstand the wear imposed by the chain, it is advisable that a high speed carbon or carbide tip drill bit be used to bore the apertures for detachably mounting the safety attachment on the saw guide. Accordingly, another object of the invention is the provision of a template to accurately guide placement of the apertures and to center the drill bit during the boring operation and a carbide tip drill bit with the safety attachment as a kit for use in equipping the chain saw with the safety attachment.
The invention possesses other objects and features of advantage, some of which, with the foregoing will be apparent from the following description and the drawings. It is to be understood that the invention is not limited to the embodiment illustrated and described since it may be embodied in various forms within the scope of the appended claims.